protected override void DoEmitCode(CompilerTarget target, StackSemantics stackSemantics)
{
//Jumps need special treatment for label resolution
if (Instruction.Arguments == -1)
{
switch (Instruction.OpCode)
{
case OpCode.jump:
target.EmitJump(Position, Instruction.Id);
break;
case OpCode.jump_t:
target.EmitJumpIfTrue(Position, Instruction.Id);
break;
case OpCode.jump_f:
target.EmitJumpIfFalse(Position, Instruction.Id);
break;
case OpCode.leave:
target.EmitLeave(Position, Instruction.Id);
break;
default:
goto emitNormally;
}
}
else
goto emitNormally;
return;
emitNormally:
target.Emit(Position, Instruction);
}
protected override void DoEmitCode(CompilerTarget target, StackSemantics stackSemantics)
{
if(stackSemantics == StackSemantics.Value)
throw new NotSupportedException("Try-catch-finally blocks cannot be used with value stack semantics (They don't produce values)");
var prefix = "try\\" + Guid.NewGuid().ToString("N") + "\\";
var beginTryLabel = prefix + "beginTry";
var beginFinallyLabel = prefix + "beginFinally";
var beginCatchLabel = prefix + "beginCatch";
var endTry = prefix + "endTry";
if (TryBlock.IsEmpty)
if (FinallyBlock.IsEmpty)
return;
else
{
//The finally block is not protected
// A trycatchfinally with just a finally block is equivalent to the contents of the finally block
// " try {} finally { $code } " => " $code "
FinallyBlock.EmitEffectCode(target);
return;
}
//Emit try block
target.EmitLabel(Position, beginTryLabel);
target.Emit(Position,OpCode.@try);
TryBlock.EmitEffectCode(target);
//Emit finally block
target.EmitLabel(FinallyBlock.Position, beginFinallyLabel);
var beforeEmit = target.Code.Count;
FinallyBlock.EmitEffectCode(target);
if (FinallyBlock.Count > 0 && target.Code.Count == beforeEmit)
target.Emit(FinallyBlock.Position, OpCode.nop);
target.EmitLeave(FinallyBlock.Position, endTry);
//Emit catch block
target.EmitLabel(CatchBlock.Position, beginCatchLabel);
var usesException = ExceptionVar != null;
var justRethrow = CatchBlock.IsEmpty && !usesException;
if (usesException)
{
//Assign exception
ExceptionVar = _GetOptimizedNode(target, ExceptionVar) as AstGetSet ?? ExceptionVar;
ExceptionVar.Arguments.Add(new AstGetException(File, Line, Column));
ExceptionVar.Call = PCall.Set;
ExceptionVar.EmitEffectCode(target);
}
if (!justRethrow)
{
//Exception handled
CatchBlock.EmitEffectCode(target);
}
else
{
//Exception not handled => rethrow.
// * Rethrow is implemented in the runtime *
//AstThrow th = new AstThrow(File, Line, Column);
//th.Expression = new AstGetException(File, Line, Column);
//th.EmitCode(target);
}
target.EmitLabel(Position, endTry);
target.Emit(Position,OpCode.nop);
var block =
new TryCatchFinallyBlock(
_getAddress(target, beginTryLabel), _getAddress(target, endTry))
{
BeginFinally =
(!FinallyBlock.IsEmpty ? _getAddress(target, beginFinallyLabel) : -1),
BeginCatch = (!justRethrow ? _getAddress(target, beginCatchLabel) : -1),
UsesException = usesException
};
//Register try-catch-finally block
target.Function.Meta.AddTo(TryCatchFinallyBlock.MetaKey, block);
target.Function.InvalidateTryCatchFinallyBlocks();
}